1. Field of the Invention
The present invention relates to a vehicle driving force control device capable of generating an appropriate driving force in response to changing road surface condition.
2. Description of the Related Art
In recent years, various vehicles which are equipped with an electronic controlled throttle valve capable of arbitrarily setting a driving force of the vehicle to accelerator operation of a driver as a vehicle driving force control device have come into practical use.
For example, in Japanese Unexamined Patent Application Publication No. 2003-227385, a technique that in a vehicle equipped with an electronic controlled throttle valve having a traction control function, when deceleration of a target torque of an engine is carried out by the traction control, it is forbidden to employ a control method of feedback control as the control of the electronic controlled throttle valve for approximating an actual engine torque to the target torque of the engine by the traction control has been disclosed.
However, in the technique for electronic controlled throttle valve discussed in the above-described Japanese Unexamined Patent Application Publication No. 2003-227385, because driving force control is carried out after the traction control is operated, the responsiveness is slow. Accordingly, it can be assumed to provide a driving force characteristic (characteristic of a driving force of a vehicle to an accelerator operation of a driver) which does not previously require traction control. However, if the characteristic is set based on drivability on a road having high friction coefficient, it is apt to slip on a road having low friction coefficient, and on the contrary, if the characteristic is set based on the drivability on the road having the low friction coefficient, the drivability is apt to be impaired on the road having the high friction coefficient.
The present invention has been made in view of the above-described disadvantages, and it is an object of the present invention to provide a vehicle driving force control device capable of ensuring excellent drivability and reducing disorder of behavior of a vehicle due to an unexpected slipping of tire and ensuring stability of the vehicle and reducing driver's burden without traction control under any road surface condition.